Double couplings are used in so-called double coupling transmissions or parallel transmissions for motor vehicles and are used for the switchable transmission of rapid rotational movements. They generally have a coupling cage with a plurality of pressure plates which are held in a torque-proof and axially movable manner in the coupling cage and driving discs arranged between the pressure plates. The coupling cage and the driving discs are respectively connected to hub bodies which may be positioned for mounting on gear shafts and for torque transmission to said gear shafts. The coupling cage, the pressure plates, the driving discs and the hub bodies form a structural unit which after assembly has to be balanced. For balancing the assembled constructional unit of a double coupling, it is necessary to receive and to retain the coupling cage and the driving discs by means of the hub body in a position corresponding to the subsequent installed position in the gearbox. It is also expedient if the driving discs are able to be retained in at least two different rotational angular positions relative to the coupling cage, in order to increase further the balancing accuracy by means of a second balancing process with rotated driving discs.
The object of the invention is to provide a device for receiving a multi-part constructional unit of a double coupling in a balancing machine which fulfils the aforementioned requirements and permits balancing of the constructional unit with a high degree of accuracy. The device is intended, moreover, to be able to be handled easily and reliably.
According to the invention, the device comprises a receiving mandrel which can be driven in rotation about its longitudinal axis and has a first portion for receiving and centering a first coupling part and a second portion arranged at its free end for receiving and centering at least one second coupling part, a first clamping device which is arranged on the first portion, can be moved by spring force into a clamping position and has a clamping face coaxial with the longitudinal axis of the receiving mandrel and a centering means which is arranged on the second portion and by means of which the second coupling part can be coupled in a torque-proof manner with the receiving mandrel in at least one angle position.
The device according to the invention permits the centering and clamping of the coupling cage by means of the receiving mandrel and the first clamping device and the centering of one or more hub bodies of the driving discs by means of the centering means. The centering means may have a second clamping device or a removable centering ring.
The first clamping device of the device according to the invention is used for clamping the first coupling part, said coupling part in particular being the hub of the coupling cage. According to the design of the hub, the clamping device may be designed to act internally or to act externally. An internally acting clamping device preferably has a radially expandable clamping sleeve which is arranged on the receiving mandrel so as to be axially movable and can rest against a conical face of the receiving mandrel. The clamping sleeve may be a slotted double conical sleeve which is expandable by means of a conical actuating sleeve arranged displaceably on the receiving mandrel. A clamping chuck resting on an annular flange of the receiving mandrel is particularly expedient as an externally acting clamping device.
A compression spring is provided for actuating the first clamping device, the receiving mandrel having a longitudinal hole, in which there are arranged the compression spring and an axially movable actuating element transmitting the force of the compression spring onto the clamping device.
The second clamping device of the centering means is according to the invention also movable by spring force into the clamping position, the receiving mandrel having a longitudinal hole in which there are arranged a compression spring and an axially movable actuating element transmitting the force of the compression spring onto the clamping device. The second clamping device may comprise at least one set of clamps comprising annular clamping discs and means for axially tightening the clamping discs. It may further be provided that the first and the second clamping devices are able to be actuated in succession by the same actuating element in such a way that one clamping device is releasable when the other clamping device is clamped. Alternatively, the clamping devices may be able to be actuated by two mutually independent actuating elements.
In a further advantageous embodiment, the second portion of the receiving mandrel can form a centering pin which carries a centering ring as a centering means which is releasably held on the centering pin, has a centering face for centering a second coupling part and is able to be coupled in a torque-proof manner to the receiving mandrel in at least one angular position. As the centering ring may be removed, the centering bore of the hub body, for example of the coupling cage, retained by the first clamping device may have a smaller diameter than the centering bore of a hub body retained by the centering ring, for example of the driving discs.
The centering bores of the driving discs are generally provided with teeth which are used for torque transmission to the corresponding gear shafts, the hub bodies also being centered on the gear shafts by means of the tooth profiles. For accurate balancing of the double coupling, therefore, the centering faces of the receiving mandrel and the centering ring are also provided with teeth corresponding to the gear shaft teeth. In order to facilitate the insertion of the receiving mandrel and the centering rings into the toothed bores of the hub bodies, the teeth on the receiving mandrel and on the centering ring on the insertion side are reduced and/or tapered in the axial and radial directions toward the end of the teeth.
During balancing, the transmission even of small torques is also required between the receiving mandrel, the centering ring and the parts of the double coupling when accelerating to balancing speed and stopping after the balancing. Moreover, the parts of the double coupling which may be rotated relative to one another have to be prevented from a relative movement during the balancing process. In order to achieve this in a simple manner by means of the centering ring, the centering ring has on its insertion side coupling recesses with which coupling projections configured on the receiving mandrel engage when the centering ring is connected to the centering pin. Preferably, a plurality of coupling recesses and/or coupling projections are provided, so that the centering ring can be coupled in a torque-proof manner with the coupling pin in a plurality of rotational angle positions.
A detent which can be locked in an interlocking manner, for example a ball detent, may be provided on the centering pin for axially fixing the centering ring.